The invention relates generally to an apparatus for charging an electrical energy source and more particularly to a battery charger for an underwater electro-acoustic measuring or position-finding apparatus, having a water-tight housing in which an energy dissipating load is situated together with a chargeable battery for current supply.
An electro-acoustic position-finding transmitter for deep sea use is disclosed in "Ocean Master," a catalogue published by Charles Kerr Enterprises Inc., beginning on page 118 (1971 Edition). The transmitter includes various electrical equipment and a battery secured within a hermetically sealed housing. The battery supplies power to the electrical equipment. Periodically, the housing is opened and the battery is re-charged.
Opening of the housing permits the unavoidable spillage and seepage of sea water onto the delicate electrical equipment. In addition, the sealing surfaces of the housing and the sealing arrangement itself are usually damaged, causing leakage. When used at sea, even small scratches or hair cracks in the sealing element permit entry of sea water into the interior chamber of the transmitter housing.
At page 364 of the same catalogue, a second transmitter is shown wherein the electrical load and battery are in separate pressure-resistant housings. Electrical contacts in the intermediate space permit interconnection of the load and battery. In this constructional form, the hermetically sealed housings need not be opened to charge the battery. However, the contacts require protection, such as a suitable grease. But for deep sea use, this technical solution becomes unworkable without constant monitoring and considerable expense.